Weird sound like a thumping.

Could be excess condensation built up in your exhaust, partially plugged cats; since it happens at idle as well, that eliminate all the rotating assemblies (wheels, tires, CV joints), the sound can only be coming from engine/exhaust. IF the sound goes away after driving for a while, then it may well be water in exhaust.

It doesnt stop even after being ran for awhile

If you hear it at idle, then park the car with engine running and walk around it listening closely for where noise is coming from. Pop the hood and get your head in there, buy or borrow a mechanic's stethoscope or use a metal pipe, rod, large screwdriver to your ear and listen to everything (just be cautious around the fan and serpentine belt.